Blood Mineral Composition in Ruminants

Abstract
Trichloracetic acid soluble whole blood minerals were measured each 3 mo. in samples from 236 Guernsey cows to determine mineral levels under herd conditions. The means observed were: P, 6.1; Mg, 2.3; Ca, 7.4; Na, 281 and K, 52 mg./100 ml. Positive correlations were found for Mg with Ca and K;; and for Ca with Na and K; and a negative correlation for Na with K. Month of pregnancy affected P, Na, and K. Month of lactation was related to P, Mg, Ca, and Na. Seasonal differences were shown for Mg, Ca and Na. Sire effects were significant for P, Mg, Na and K. Milk production was positively correlated with Mg and negatively correlated with K. The Ca:P ratio was largest during the first half of pregnancy. A small ratio of 1.14 in the second month of lactation was preceded in the first month and followed by an increased ratio in the third to the seventh month of lactation. A significant effect of age was found for P and K. A general inverse relationship was observed for P and K among age groups. Copyright © 1968. American Society of Animal Science . Copyright 1968 by American Society of Animal Science